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Area forecast discussion 
National Weather Service New Orleans la
1139 am CDT Thursday Jul 2 2015

extensive cloud cover mainly in MVFR ranges this morning should
lift to VFR scattered-broken by 19z. Cloud cover should also limit heating
to maintain only isolated convection this afternoon...too low
probability to include at any of the terminals at this time. 24/rr


Previous discussion... /issued 811 am CDT Thursday Jul 2 2015/

.Sounding discussion...
The sounding today is moist and unstable with precipitable water above average at
2.04 inches and mixed layer cape at 2050 j/kg. These numbers are
partially a product of the extra moisture at the surface due to
showers this morning. Limitations on storms later today will come
from subsidence aloft and dry air mixing out the moist surface
conditions. The subsidence features are subtle right now... with a
slight cap at 850 mb and a relatively shallow lapse rate in the
cloud layer from 650 to 500 mb. We are still expecting less
coverage than the past few days... but any good lift at the surface
this afternoon from local boundaries or even heating could result
in scattered storms. Winds are westerly from the surface to 500 mb
then become northerly above.


Previous discussion... /issued 337 am CDT Thursday Jul 2 2015/


Westward extension of Bermuda high covers about eastern two thirds
of the Gulf of Mexico this morning. Upper trough axis extends along
about 82w longitude with closed upper high centered over The Four
Corners area. Scattered showers and a few thunderstorms moving
offshore of St. Bernard and Plaquemines parishes...and are likely
to be limited to coastal waters by 12z. Looks like echoes radar is
picking up west of Interstate 55 probably middle level moisture that
is not reaching the surface. Temperatures at 3 am ranged from 72
at McComb to 84 at Boothville and Port Fourchon.

Short term...

Really little change in forecast scenario through Saturday. Any
convection today is likely to be limited to Mississippi coast and
eastern coastal waters...and slight chance probability of precipitation that we are
carrying there may even be too high. Will continue with the
consensus of dry weather for tonight through Friday night in most
areas. Northern stream shortwave moving through the middle
Mississippi and Tennessee valleys on Saturday should weaken the
high pressure across the area enough to allow the development of
scattered convection. Most convection should weaken with loss of
heating on Saturday...with only small chances of convection after
sunset in most areas.

The slightly drier air today and Friday should permit highs to be
a couple degrees warmer than the past few days. More cloud cover
and precipitation will temper highs a few degrees on Saturday. No
large discrepancies in temperatures and a blend should work pretty
well. 35

Long term...

Potential for scattered convection will continue on Sunday before
upper ridging makes another attempt to move into the area. European model (ecmwf)
solution beyond Sunday is somewhat drier than the GFS solution
with the western ridge building into the area. Have gone with a
blended solution on probability of precipitation...which fits with neighboring offices for
now. If the European model (ecmwf) becomes the preferred solution...later shifts
may need to lower probability of precipitation and bump high temperatures up a few
degrees. 35


Much less ts activity expected today. Strong inversion will set up
overnight will promote low ceiling formation but should be a few
hours before and shortly after sunrise. Will tempo these at about
300ft with the southern most terminals experiencing around 600ft.
Visible will restrict to around 3sm as well but will show 1sm for sites
to the north with 1/2sm for mcb and possibly asd. Will take another
look before 12z taf package issuance though. 17/te


An expansive ridge of high pressure over most of the Gulf of
Mexico...extending west from the typical summertime Bermuda
ridge...will remain in place through the weekend. As the reflective
high settles over the NE Gulf winds will shift from a southwest to a
southeast direction. But wind speeds are expected to get no stronger
than the 10-15 knots range. Most areas will experience speeds of 5-10
knots. Seas will remain anywhere from 1 to 3 feet. 17/te

Decision support...

Activities...river flood warnings on Mississippi River from Red
River Landing to Baton Rouge.

Decision support services (dss) code legend
green = no weather impacts that require action
blue = long fused watch/warning/advisory in effect or high
visibility event
yellow = heightened impacts with short fused watch/warning/advisory
issuances; radar support
Orange = high impacts - slight to moderate risk severe; nearby
tropical events; hazmat or other large episodes
red = full engagement for moderate risk severe and/or direct
tropical threats; events of National significance


Preliminary point temps/pops...
mcb 91 73 92 73 / 10 10 10 20
btr 92 74 93 74 / 10 10 10 10
asd 92 76 92 77 / 10 10 10 10
msy 92 77 92 77 / 10 10 10 10
gpt 89 78 90 78 / 20 10 10 10
pql 89 76 91 76 / 20 10 10 10


Lix watches/warnings/advisories...


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